[The effect of glycine and gamma-aminobutyric acid on the evoked activity of the spinal cord motor neurons in the lamprey].

The influence of bath application of glycine (10(-5)-10(-3) mol/l) and gamma-aminobutyric acid (10(-5)-10(-2) mol/l) on the monosynaptic EPSPs evoked in motoneurons by stimulation of a descending tract and individual Müller axons was studied in spinal cord-notochord preparation of lamprey (Lampetra fluviatilis). Both amino acids hyperpolarized the motoneuron membrane and depressed the evoked synaptic activity. But the inhibitory effect of glycine was stronger and it was revealed at lower concentrations as compared to that of GABA. It is concluded that glycine is more effective in blocking the postsynaptic motoneuron activity in comparison with GABA in the spinal cord of lamprey.